Friday, November 17, 2006

CHC theory: Fluid intelligence (Gf)

What is fluid intelligence (Gf)?According to the APA Dictionary of Psychology, fluid abilities are those abilities "such as memory span and mental quickness, that are functionally related to physiological condition and maturation. Fluid abilities appear to increase during childhood and to deteriorate , to some extent, in old age" (p. 381).

Drawing inferences of a generalized conclusion from particular instances (Induction-I) and the ability to derive conclusions by reasoning, specifically: inference in which the conclusion about particulars follows necessarily from general or universal premises (General Sequential Reasoning-RG; aka, deductive reasoning), are generally considered the hallmark indicators of Gf.

Gf has often been linked to cognitive complexity which can be defined as a greater use of a wide and diverse array of elementary cognitive processes during performance. Cognitive complexity is often defined as the ability to deal with a multitude of elements and the relations among the elements. Cognitively complex tasks (compared to cognitively less demanding or simple tasks) require the processing of more components and more flexible and adaptive assembly and reassembly of processing from component to component. Cognitive complexity should not be considered isomorphic with abstract thinking, a characteristic often associated with Gf.

The primary defining feature of cognitive complexity is the mental juggling of multiple elements/stimuli within the confines of working memory. This association with working memory has resulted in the hypothesis that Gf may either be isomorphic with working memory, or, at a minimum, heavily dependent on working memory capacity.

Narrow Gf abilities

Induction (I) is the ability to discover the underlying characteristic (e.g., rule, concept, principle, process, trend, class membership) that underlies a specific problem or a set of observations, or to apply a previously learned rule to the problem. Reasoning from specific cases or observations to general rules or broad generalizations. Often requires the ability to combine separate pieces of information in the formation of inferences, rules, hypotheses, or conclusions.

According to Carroll (1993): "Inductive tasks are those that require subjects to inspect a class of stimulus materials (nearly always with more than one instance) and infer (induce, educe) a common characteristic underlying these materials -- a concept , a class membership, a rule, a process, a trend, or a causal relation, for example" (p.238).

forecasting the weather from information on wind current, barometric pressure, and other information

determining the guilty parties from available evidence

predicting election results based on demographics, polls and voting trends.

General Sequential (deductive) Reasoning (RG) is the ability to start with stated assertions (rules, premises, or conditions) and to engage in one or more steps leading to a solution to a problem. The processes are deductive as evidenced in the ability to reason and draw conclusions from given general conditions or premises to the specific. Often known as hypothetico-deductive reasoning.

According to Carroll (1993): "The dominant feature of these RG factors is that they emphasize the ability to reason and draw conclusions from given conditions or premises, often in a series of two of more sequential steps. Above all, the processes are deductive, in the sense that there is very little load of induction or rule-finding" (p. 234). "The best tests of this factor impose little requirement on the subject to induce (educe) relationship or class memberships, since these relations hips and class memberships are stated or otherwise immediately apparent to most subjects. Preferably these tests should be administered without a time limit, or at least scored in such a way that the subject's level of mastery of deductive skills, rather than speed in processing information, is emphasized." ( p. 234)

According to Carroll (1993): "These are factors requiring reasoning based on mathematical properties and relationships. The reasoning processes may be either inductive or deductive, or some combination of them" (p. 238-241)

Speed of Reasoning (RE) is the speed or fluency in performing reasoning tasks (e.g., quickness in generating as many possible rules, solutions, etc., to a problem) in a limited time. It is also listed under Gs (processing speed) in CHC theory.

Piagetian Reasoning (RP) is the ability to demonstrate the acquisition and application (in the form of logical thinking) of cognitive concepts as defined by Piaget's developmental cognitive theory. These concepts include seriation (organizing material into an orderly series that facilitates understanding of relationships between events), conservation (awareness that physical quantities do not change in amount when altered in appearance), classification (ability to organize materials that possess similar characteristics into categories), etc. The relation between RP with reasoning abilities measured by more conventional tests (I, RG, RQ) is not clear.

According to Carroll (1993): "We can draw only the general conclusion that there are several dimensions of individual differences in Piagetian reasoning ability, perhaps as many as three, but that all measures of Piagetian reasoning tend to have high loadings on a general factor. The relation of possibly different kinds of Piagetian reasoning to the kinds of reasoning measured by more conventional tests is not yet clear from available research."

Many psychometric tasks have been devised to measure Gf, with the major design characteristics being the use of figural or symbolic stimuli and the minimization of task components that draw upon a person's store of acquired knowledge.

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About Me

Dr. Kevin McGrew is Director of the Institute for Applied Psychometrics (llc). Additional information, including potential conflicts of interest resulting from commercial test development or other consultation, can be found at The MindHub(TM; http://www.themindhub.com ). General email contact is iap@earthlink.net.